Bloch-type magnetic skyrmions in two-dimensional lattices.

Magnetic skyrmions in two-dimensional lattices are a prominent topic of condensed matter physics and materials science. Current research efforts in this field are exclusively constrained to Néel-type and antiskyrmions, while Bloch-type magnetic skyrmions are rarely explored. Here, we report the discovery of Bloch-type magnetic skyrmions in a two-dimensional lattice of MnInP2Te6, using first-principles calculations and Monte-Carlo simulations. Arising from the joint effect of broken inversion symmetry and strong spin-orbit coupling, monolayer MnInP2Te6 presents large Dzyaloshinskii-Moriya interaction. This, along with ferromagnetic exchange interaction and out-of-plane magnetic anisotropy, gives rise to skyrmion physics in monolayer MnInP2Te6, in the absence of a magnetic field. Remarkably, different from all previous works on two-dimensional lattices, the resultant magnetic skyrmions feature Bloch-type magnetism, which is protected by D3 symmetry. Furthermore, Bloch-type magnetic bimerons are also identified in monolayer MnTlP2Te6. The phase diagrams of these Bloch-type topological magnetisms under a magnetic field, temperature and strain are mapped out. Our results greatly enrich the research on magnetic skyrmions in two-dimensional lattices.

Ferroelectrically tunable magnetic skyrmions in two-dimensional multiferroics.

Magnetic skyrmions are topologically protected entities that are promising for information storage and processing. Currently, an essential challenge for future advances of skyrmionic devices lies in achieving effective control of skyrmion properties. Here, through first-principles and Monte-Carlo simulations, we report the identification of nontrivial topological magnetism in two-dimensional multiferroics of Co2NF2. Because of ferroelectricity, monolayer Co2NF2 exhibits a large Dzyaloshinskii-Moriya interaction. This together with exchange interaction can stabilize magnetic skyrmions with the size of sub-10 nm under a moderate magnetic field. Importantly, arising from the magnetoelectric coupling effect, the chirality of magnetic skyrmions is ferroelectrically tunable, producing the four-fold degenerate skyrmions. When interfacing with monolayer MoSe2, the creation and annihilation of magnetic skyrmions, as well as phase transition between skyrmion and skyrmion lattice, can be realized in a ferroelectrically controllable fashion. A dimensionless parameter κ' is further proposed as the criterion for stabilizing magnetic skyrmions in such multiferroic lattices. Our work greatly enriches the two-dimensional skyrmionics and multiferroics research.

Multiple Topological Magnetism in van der Waals Heterostructure of MnTe2/ZrS2.

Topological magnetism in low-dimensional systems is of fundamental and practical importance in condensed-matter physics and material science. Here, using first-principles and Monte Carlo simulations, we present that multiple topological magnetism (i.e., skyrmion and bimeron) can survive in van der Waals heterostructure MnTe2/ZrS2. Arising from interlayer coupling, MnTe2/ZrS2 can harbor a large Dzyaloshinskii-Moriya interaction. This, combined with exchange interaction, yields an intriguing skyrmion phase under a tiny magnetic field of 75 mT. Meanwhile, upon harnessing a small electric field, magnetic bimeron can be observed in MnTe2/ZrS2, suggesting the existence of multiple topological magnetism. Through interlayer sliding, both topological magnetisms can be switched on-off. In addition, the impacts of d∥ and Keff on these spin textures are revealed, and a dimensionless parameter κ is utilized to describe their joint effect. These explored phenomena and insights not only are useful for fundamental research in topological magnetism but also enable novel applications in nanodevices.

Theoretical Prediction of Antiferromagnetic Skyrmion Crystal in Janus Monolayer CrSi2N2As2.

An antiferromagnetic skyrmion crystal (AF-SkX), a regular array of antiferromagnetic skyrmions, is a fundamental phenomenon in the field of condensed-matter physics. So far, very few proposals have been made to realize the AF-SkX, and most have been based on three-dimensional (3D) materials. Herein, using first-principles calculations and Monte Carlo simulations, we report the identification of AF-SkX in a two-dimensional lattice of the Janus monolayer CrSi2N2As2. Arising from the broken inversion symmetry and strong spin-orbit coupling, a large Dzyaloshinskii-Moriya interaction is obtained in the Janus monolayer CrSi2N2As2. This, combined with the geometric frustration of its triangular lattice, gives rise to the skyrmion physics and long-sought AF-SkX in the presence of an external magnetic field. More intriguingly, this system presents two different antiferromagnetic skyrmion phases, and such a phenomenon is distinct from those reported in 3D systems. Furthermore, by contacting with Sc2CO2, the creation and annihilation of AF-SkX in Janus monolayer CrSi2N2As2 can be achieved through ferroelectricity. These findings greatly enrich the research on antiferromagnetic skyrmions.

Spontaneous Magnetic Skyrmions in Single-Layer CrInX3 (X = Te, Se).

The realization of magnetic skyrmions in nanostructures holds great promise for both fundamental research and device applications. Despite recent progress, intrinsic magnetic skyrmions in two-dimensional lattice are still rarely explored. Here, using first-principles calculations and Monte Carlo simulations, we report the identification of spontaneous magnetic skyrmions in single-layer CrInX3 (X = Te, Se). Because of the joint effect of broken inversion symmetry and strong spin-orbit coupling, inherent large Dzyaloshinskii-Moriya interaction occurs in both systems, endowing the intriguing Néel-type skyrmions. By further imposing moderate magnetic field, the skyrmion phase can be obtained and is stable within a wide temperature range. Particularly for single-layer CrInTe3, the size of skyrmions is sub-10 nm and the skyrmion phase can be maintained at an elevated temperature of ∼180 K. In addition, the phase diagrams of their topological spin textures under the variation of magnetic parameters of D, J, and K are mapped out.

How to prophylactically alleviate postembolization syndrome following transarterial chemoembolization?: Protocol of a double blinded, randomized, placebo-controlled trial.

INTRODUCTION: Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer, and most patients in China are diagnosed at the intermediate or later stages, which is not suitable for the first line therapies. Transarterial chemoembolization (TACE) is a commonly selected therapeutic option for intermediate and later stage HCC in China, but patients often suffer from postembolization syndrome (PES), manifesting as fever, liver area pain, nausea, vomiting, paralyzed intestinal obstruction, and abdominal pain after TACE. We try to conduct a double blinded, randomized, placebo-controlled clinical trial to observe whether Chaihu Guizhi decoction (CGD), a classic traditional Chinese formula, could prophylactically alleviate the incidence of PES in HCC patients after TACE. METHODS: Patients will be randomly assigned sequentially in a 1:1 ratio by using preformed randomization envelopes. After TACE procedures, patients in the treatment group will be administrated with Chinese herbal formula CGD, and patients in the control group with CGD simulations, twice a day, continuously for 7 days. The outcomes are the incidence of PES hospitalization and, complications. SPSS version 22 (IBM, Chicago, IL) will be used for the data, and a P < .05 will be considered statistically significant. CONCLUSIONS: The findings will explore the prophylactic effect of CGD in alleviating the incidence of PES following TACE in HCC patients. TRIAL REGISTRATION: OSF Registration number: DOI 10.17605/OSF.IO/FKRSN.

Tl2O/WTe2 van der Waals heterostructure with tunable multiple band alignments.

Two-dimensional van der Waals heterostructures (vdWHs) with tunable band alignment can be very useful for developing minimized multifunctional and controllable devices, but so far they are scarcely reported. Here, using first-principles calculations, we systematically investigate the electronic properties of Tl2O/WTe2 vdWH. Our results indicate that it is a direct bandgap semiconductor harboring a straddling type-I band alignment, with the conduction band minimum (CBM) and valence band maximum (VBM) both from two-dimensional WTe2. Interestingly, upon introducing feasible external strain or electric field, its band alignment can be easily transformed into staggered type-II, with CBM and VBM separated in different layers, achieving the long-sought tunable multiple band alignments. Along with this, the intriguing direct-to-indirect bandgap transition is also achieved in Tl2O/WTe2 vdWH. Our work thus provides a promising candidate in the field of two-dimensional multifunctional and controllable electronics.

Comparative study on self-absorption of laser-induced tungsten plasma in air and in argon.

The onset of self-absorption of laser-induced plasma poses a problem for converting emission line intensities to concentrations, which is one of the main bottlenecks in quantitative laser-induced breakdown spectroscopy (LIBS) measurements. In this paper, the effects of atmosphere and laser fluence on self-absorption reduction of the plasma induced on tungsten-copper alloy target were investigated with nanosecond infrared (1064 nm) laser pulse over a range of 2.9 to 18.2 J/cm2. The time-resolved features of self-absorption, and temperature and electron density of the plasma were characterized in atmospheric air and argon, respectively. The experimental results show the effect of self-absorption can be significantly reduced by increasing the laser pulse energy. The argon atmosphere is more helpful for self-absorption reduction. The time-resolved diagnostics of emission spectra in the early stage of the plasma formation are very effective to prevent self-absorption to improve the LIBS analytical performance.

Single-Layer Ag2S: A Two-Dimensional Bidirectional Auxetic Semiconductor.

Two-dimensional auxetic materials have attracted considerable attention due to their potential applications in medicine, tougher composites, defense, and so on. However, they are scare especially at low dimension, as auxetic materials are mainly realized in engineered materials and structures. Here, using first-principles calculations, we identify a compelling two-dimensional auxetic material, single-layer Ag2S, which possesses large negative Poisson's ratios in both in-plane and out-of-plane directions, but anisotropic ultralow Young's modulus. Such a coexistence of simultaneous negative Poisson's ratios in two directions is extremely rare, which is mainly originated from its particular zigzag-shaped buckling structure. In addition, contrary to the previously known metal-shrouded single-layer M2X (M = metal, X = nonmetal), single-layer Ag2S is the first nonmetal-shrouded M2X. Electronic calculations show that it is an indirect-gap semiconductor with gap value of 2.83 eV, and it can be turned to be direct with strain. These intriguing properties make single-layer Ag2S a promising auxetic material in electronics and mechanics.

The variation of AkT/TSC1-TSC1/mTOR signal pathway in hepatocytes after partial hepatectomy in rats.

OBJECTIVE: The aim of this study was to investigate the role and regulatory mechanisms of Akt/TSC1-TSC2/mTOR signal pathway on the hepatocyte growth and proliferation after partial hepatectomy in rats. METHODS: We used the animal model of 70% hepatectomy, separated and cultivated hepatocytes. According to the different time points after partial hepatectomy, it could be grouped into 0 h, 2 h, 6 h, 24 h and 72 h. According to the different kinds of specific inhibitor in the nutritive medium after the separation of hepatocytes, it could be grouped into Triciribine (TR), Rapamycin (RA) and Control (CO). We investigated (3)H-Leucine incorporation into protein, the cross section areas of hepatocytes, and detected cell cycle through FCM. The expressions of phosphorylated protein TSC2 and mTOR were observed. RESULTS: (1) The content of phosphorylated protein TSC2 in group CO began to increase at 2 h and got to the peak at 6 h but declined at 24 h. The content of phosphorylated protein TSC2 in group RA had the same variation with that of phosphorylated protein TSC2 in group CO. (2) At the time point of 0 h, 2 h, 6 h and 24 h after operation, the incorporation efficiency of (3)H-Leucine in groups RA and TR was different from that in group CO in statistics (P<0.01). (3) It could be seen that the cross section areas of hepatocytes in groups RA and TR were different from that in group CO in statistics at 2 h and 6 h after operation (P<0.05). (4) Comparing with the other two inhibitor groups (TR and RA), the number of cells during the period of G0/G1 in group CO became fewer, while the number of cells during the period of S and G2/M grew obviously (referring to Fig. 8). After operation, each time point was different from the inhibitor groups obviously (P<0.05 or P<0.01). The peak declined greatly at 24 h and 72 h after operation. CONCLUSIONS: These data strongly suggest the effects of Akt/TSC1-TSC2/mTOR signal pathway on hepatocyte growth, protein synthesis and cell cycle, and prove its contribution to liver regeneration.

[Study on the effect of extraction behaviour of molybdenum (V) thiocyanate complex in the dimethyl sulfoxide and water system by spectrophotometry].

In this paper the effect of petroleum sulfoxide-carbon tetrachloride used as extractant on the extraction behaviour of molybdenum (V) thiocyanate complex at different concentration of dimethyl sulfoxide and water system is studied by spectrophotometry. The mixture ratio of extraction is directly calculated using spectrophotometric data. Functional relation of mixture ratio and concentration of thiocyanate in mixed solution is discussed. By increasing the percent of volume of dimethyl sulfoxide in mixed solution, the effects of mixture ratio and percentage of extraction were studied. The experimental results were explained. It shows that the extraction system of MoO (SCN)3 has an application value.